The present invention relates to a mounting apparatus for pipes, and more particularly to a mounting apparatus having a plurality of bands having a thermoplastic coating.
Common mounting apparatuses are known which serve to mount a cable to a wall and which do not have to bear any particular forces. There are, however, other applications in which the mounting apparatuses have to bear considerable forces and in which special requirements exist with reference to corrosion protection.
A requirement of this kind is to be found in offshore oil and gas production. Pipes having diameters of the order of magnitude of 50 cm must be secured to drilling rigs, platforms, ships and foundations which lie deep below the water surface.
The reliable attachment of such pipes to supporting structures is problematic and frequently carried out by means of iron or steel hoops. However, subsequent surface treatment of the pipes fails to include the regions where the pipe hoop contacts the pipe surface. The pipes will thus corrode due to the moist environment and diverse metals.
U.S. Pat. No. 3,668,740 discloses a high strength, non-corrodible strap of composite materials, which is intended for anchoring underground storage tanks on foundations to prevent them lifting due to buoyancy forces when the tank is partly or fully empty. The strip is manufactured by drawing structural members, such as glass filaments, through a pot containing a duroplastic resin, such as polyester, bisphenol, or epoxy resins. The resin impregnated filaments are then wound into a continuous or endless band. The number of revolutions required is determined by the desired strength of the finished strap. For example, a strap of 44 mm width and 6.25 mm thickness can be wound with twenty revolutions of a bundle of glass filaments to provide a tensile strength of 20,000 pounds. The length of the finished strap is determined by the distance between the axially directed winding fingers of a winding apparatus. The axially directed fingers are adjustable along radially directed arms of the winding apparatus to vary the size of the loop used to form the strap.
After the desired number of revolutions have been made, the winding apparatus is stopped and the advancing resin impregnated filaments are severed from the wound continuous band. The loose end is then pressed into the uncured resin of the wound continuous band where it is integrated into the matrix. The wound continuous band, together with two thimbles for the eyes of the finished strap, are removed from the winding apparatus and placed on a mould table. The two opposite sides of the wound continuous band are pressed together on the mould table to form an elongate strap with two eyes and the formed strap is left in the mould until the resin cures into a hard matrix.
U.S. Pat. No. 3,668,740 also specifies that the strap can also be produced by winding the filaments into the desired loop shape and then impregnating the assembled elements with resin to form the matrix of the strap construction. The impregnating resin can be applied by such methods as spraying, dipping, or injecting into a mould.
In addition to these methods of producing a wound filament strap, other structural member can be produced with reinforcing filaments extending basically longitudinally and continuously from one end of the member to the other, but not looping. The resinous matrix can be applied either by advancing the bundle of filaments through a pot of resin or impregnating after the filaments have been placed into the desired configuration. It is to be noted that this invention is not limited to the use of filaments in the form of rovings, but also contemplates the use of strands, yarns, or woven filaments.
While glass filaments and polyester resin are the preferred constituents used for the straps of U.S. Pat. No. 3,668,740, it is obvious to one skilled in the art that other materials can be readily substituted. The reinforcing material can be of any high tensile strength filaments of materials such as carbon, nylon, rayon, and metals. The matrix of the strap can be made from any abuse-resistant material such as epoxy resins, vinyl, and rubber, as long as it is compatible with the reinforcing filaments. The matrix material can be selected to give particular desired effects. A soft, resilient material such as rubber could be used to form a matrix with the ability to firmly grip the object to be secured by the strap through the frictional advantages gained by compressing the matrix against the object. The advantages of such a strap would be useful in securing an object, such as a tank, against rotation when subjected to motion such as occurs aboard a ship. Other possible desired effects, such as extensibility, can be had by using the construction form of this invention with elastomeric matrix materials and reinforcing material having a high coefficient of expansion or extensibility created by twisting the filaments.
The construction described in U.S. Pat. No. 3,668,740 are, however, all very complicated, difficult to realize, and subject to significant restrictions. For example, if a winding apparatus is used, it has to be designed for a maximum circumferential length of the wound band and cannot be used for greater circumferential lengths. The curing of the thermoplastic resin presents problems not just in the finished article but also in the resin impregnating apparatus. Moreover, there are considerable difficulties in handling the resin impregnated filaments, which severely restricts the products which can be made from them.
German Patent Application 195 22 014 A1, discloses the use of flexible bands consisting of a high modulus grid fabric of polyester yarns which are coated with a protective layer of PVC. The bands can be used to interconnect a plurality of pipelines extending parallel to one another by wrapping the band once around each pipeline in turn and anchoring the two free ends of the band in the earth by means of holders.